Most current cast warewashing detergents contain a combination of caustic and carbonate. Carbonate has conventionally been included in detergents to provide alkalinity and some buffer capacity. However, the presence of carbonates can exacerbate the tendency of hard water to precipitate and scale.
Conventional detergents also commonly include phosphorus-containing materials or builders. Phosphates are multifunctional components commonly used in detergents to reduce water hardness as well as increase detergency, antiredeposition, and crystal modification. In particular, polyphosphates such as sodium tripolyphosphate and their salts are used in detergents because of their ability to prevent calcium carbonate precipitation and their ability to disperse and suspend soils. If calcium carbonates are allowed to precipitate, the crystals may attach to the surface being cleaned and may cause undesirable effects. For example, calcium carbonate precipitation on the surface of ware can negatively impact the aesthetic appearance of the ware and give the ware an unclean look. The ability of sodium tripolyphosphate to disperse and suspend soils facilitates the detergency of the solution by preventing the soils from redepositing into the wash solution or wash water. However, while effective, phosphates are subject to government regulations due to environmental and health concerns.